Install a Smiths Digital Speedometer

| 4/13/2015 3:09:00 PM

Instrument failure is a familiar issue on vintage bikes. Smiths speedometers and tachs, used on the majority of British bikes up through the late 1970s, are generally reliable. Yet with age, failure becomes increasingly common. Specialty vendors can restore many of them, and while an excellent option, it might not be the route to take with a daily rider vintage Norton or Triumph.

A major issue with vintage Smiths speedometers is the speedometer gear box, which drives the speedometer cable at the wheel. These are known to fail regularly. Recent pattern replacements haven’t been as durable as the originals, and originals haven’t been available for years. So what’s the option? For some riders, it might be a digital speedometer.

BikeMasterGoing digital has a distinct advantage; no mechanical components to fail. Instead of a gear box, a stationary pickup triggered by a magnet attached to the spinning wheel sends a signal to a processor, which calculates speed. It’s a simple proposition, but it does mean wiring up a trigger, which, while small, detracts from the vintage proposition. Fortunately, as we discovered, you can keep vintage looks while gaining modern electronics.

Smiths is still in business, and following an employee buyout in 2010 launched a new line of replacement digital speedometers and tachometers, now available in the U.S. from Smiths Gauges USA. The company, run by British bike enthusiast Tom Kullen, has engineered a simple conversion for the Smiths speedo drive so it can be used to house a digital pickup. To the casual observer, it looks stock and original.